I think the definition should include the words "if happy in your location". I would define all of them as short-lived perennials. They will fail to over-winter if the soil is too moist--they don't like wet feet in winter. Sometimes if you don't dead head black-eyed-susans they won't come back--maybe it's a survival instinct that if they haven't set seed they'll try, try again. And sometimes, and wrongly too, a plant which is typically annual is called perennial because you find it in the garden the next year--because it is a reliable reseeder. It not come back from the original roots but has successfully reseeded, perhaps even making its own little colony.

It is hard to know what to recommend without knowing the pathogen. Can you describe how the leaf is affected more? Are there spots? a coating? totally black? scorched? Can you post a pic? Are they only affected in one part of the yard? Do you have healthy plants elsewhere? Personally, if they have a fungus that reappears each year, I would dig them up, throw them out and get another plant. If there is one plant that gardeners try to find homes for, it is their divisions of black eyed susans.

I have had very different results with Black eyed suzi's. I had some rather plain ones, that where doing fabulous prior to our moving. Now I will never know the fate of them, but year over year they where thriving, increasing in size, probably by 2 to 3 times every year. I have a hard time to believe that next spring they would not come up again, unless the new home owner removed them! lol. Now, I had some really pretty Gloriosa Daisys, they where yellow with a green eye, huge flower, and really they are a black eyed suzi, I planted 3, the next spring only 1 came up. Although it florished that year! That is just how the cookie crumbed! lol. I think if you want to grow these flowers and want them to stick around, the best bet is to plant the more plain varieties, mulch them in the fall (make sure to remove excess mulch in the spring) and perhaps spread some new seed into the planting in the fall. Otherwise, you just sort of roll the dice! The best news is, they are surprisingly easy to grow from seed! And not expensive at all that way!

Nanadoll, Beautiful planting of summer beauties! Great photos, thanks for sharing them! Rudbeckia hirta (Gloriosa Daisy), is the ideal daisy, much beloved. It's a short lived perennial at best, an asset, not a liability...essentially an annual...and oh, how beautiful and easy to grow and manage it is. It gives so much in return for so little effort. There's a huge flowered double yellow, green petal centered Gloriosa Daisy that blooms its head off from seed the first year. Bushy and not a leggy grower. The flowers look like exhibition, show Chrysanthemums. Out of 10 plants, only one will come back next year, but that's OK. Easy, easy to grow from seed. It does not self sow or come true from seeds, if I can remember correctly. I may be wrong. I grew it years ago and it exceeded my greatest expectation. Nothing says summertime like a bed of: Gloriosa Daisy, any and all Echinaceas, Phlox paniculata (any varieties, especially David....not to forget the common garden Phlox), Liatris, Malva alcea fastigiata, and/or Malva moschata alba, and last but not least, Heliopsis 'Summer Sun'. Grow Rudbeckia 'Goldstrum,' at your own risk. Should be outlawed! It invades everything, and chokes itself to the point of producing junk flowers. I'm tempted to rip up the roses in favor of a bed of the above beauties. It sure would be a lot less work! Moses